There has been proposed the method for forming color images on a thermal transfer image-receiving sheet which is dyeable with a sublimable dye by using a thermal transfer sheet composed of the sublimable dye as a recording agent and a substrate on which the sublimable dye is supported. In this method, the dye is heated using a thermal head of a printer as a heating means and transferred on the image-receiving sheet to obtain the color images. The thus formed images are very clear and excellent in transparency because of the dye used, and are therefore expected to provide high-quality images which are excellent in reproducibility of half tones and gradation.
In the production of the thermal transfer image-receiving sheet, a film-forming assistant is usually used for enhancing a film-forming property of a dye receptor layer capable of receiving the sublimable dye, when applying a coating material for the dye receptor layer onto the substrate to form the layer.
As the thermal transfer image-receiving sheet produced by using the film-forming assistant, there is disclosed, for example, a heat-sensitive thermal transfer image-receiving sheet in which a dye receptor layer containing a polymer latex which is formed from an aqueous coating material, and a heat-insulating layer containing a hollow polymer, are formed on a substrate, and any one of the constitutional layers disposed on the side of the dye receptor layer is obtained by applying a coating solution containing an organic solvent having a boiling point of from 140° C. to 220° C. in an amount of 3% or less on the basis of whole solid components in the coating solution (JP 2007-190910A).